a. Field of the Invention
The present invention is related to a backlight device of a LCD display, more particularly, to a dual-faceted LCD display or a triple-faceted LCD display with only single backlight device.
b. Description of Prior Art
The LCD (Liquid Crystal Display), used as a display device, is mounted in a variety of electronic devices. A laptop (or notebook) personal computer is a typical electronic device employing a large-size liquid display screen. There is competition to develop thinner and lighter screens at larger sizes.
FIG. 1 shows a cross-sectional view of the conventional LCD display. The LCD display comprises a light guide pipe 10, a light source 12, the first optical means 20, and the first LCD panel 40.
The light guide pipe 10 is wedge-shaped or plane, comprising the first surface 10a and the second surface 10b. A reflector 15 is provided on the first surface 10a of the light guide pipe 10. The light guide pipe 10 is generally made of an acrylic resin, and has a dot pattern formed on its inner surfaces which can make the light from the light source 12 uniform over the second surface 10b. 
The light source 12, which is a cold fluorescent lamp or any other light emitter such as LED, is provided at the first edge 10c of the light guide pipe 10. The lamp reflector 13 is applied to cover the light source 12 and reflect the light into the light guide pipe 10. The light is then propagated and reflected repeatedly in the light guide pipe 10, and emitted over its second surface 10b. 
The first optical means 20 is provided on the second surface 10b of the light guide pipe 10, and applied to make the light emitted from the light guide pipe 10 uniform. The first optical means 20 is generally composed of the first diffuser 21, the first light converting film 22, the second light converting film 23, and the second diffuser 24. The first LCD panel 40 is then provided on the first optical means 20 for displaying images.
Recently, more and more electronic products need more than two LCD display, such as a dual-faceted or triple-faceted LCD display on a cell phone or a PDA (Personal Digital Assistant). At present, however, two (three) backlight devices are needed for a dual-faceted (triple-faceted) LCD display. It not only largely increases the cost of production, but also makes the LCD display bulky. It thus violates the trend to make the LCD display thinner and brighter.
Accordingly, there exists a need in the LCD display field for an improved arrangement which provides a thinner and brighter dual-faceted or triple-faceted LCD display with low production cost.